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作为C语言初学者，尝试完成了一个可以实现四则运算和单位换算的简易计算器，请多指教。 一、需求分析1、四则运算: (1) 能识别用户输入的运算(加+、减、乘*、除/)表达式并计算，如：用户输入189+219，按回车确定后可计算该加法运算的结果并打印输出，其它运算以此类推； (2)能检测表达式中的错误或不符合运算法则的情况并提示。 2、单位转换: (1)能实现长度单位换算：英寸、英尺、毫米、厘米、米； (2)能实现质量单位换算：磅、盎司、克、千克、斤、吨； (3)能实现面积单位换算：公顷、亩、平方米、平方英尺； 二、分析四则运算功能采用 switch 语句判断运算符； 单位转换功能使用全局变量存储各单位数值，采用switch语句判断单位表示； 四则运算和单位换算用两个函数实现，其中不同类型的单位换算也用函数实现； 用while语句实现循环运行。 三、程序实现笔者采用VS2008编写C语言程序，代码如下： /* 功能：实现四则运算和单位换算的简易计算器 单位换算包括长度单位、质量单位和面积单位 时间：2020/07/12 作者：抬手摘星辰 */ #include #include #include #include #define FT_TO_M ((float)0.3048) #define FT_TO_IN (12) #define IN_TO_CM (2.54) #define LB_TO_OZ (16) #define LB_TO_G (453.5924) #define OZ_TO_G (28.3595) // 四则运算 void FourArithmetic(float data1, float data2, char op) { printf("* 结果为：\n"); switch(op) { case'+': printf("%.2f + %.2f = %.2f\n",data1,data2,data1+data2); break; case'-': printf("%.2f - %.2f = %.2f\n",data1,data2,data1-data2); break; case'*': printf("%.2f * %.2f = %.2f\n",data1,data2,data1*data2); break; case'/': if(0==data2) printf("Division by zero!\n"); else printf("%.2f / %.2f = %.2f\n",data1,data2,data1/data2); break; case'%': printf("%.2f% % %.2f = %.2f\n",data1,data2,(int)data1%(int)data2); break; default: printf("* 无效的运算符号，请重新输入！\n"); } } //长度单位换算 void LengthUnit(float data1, char op1[5], char op2[5]) { int i = 0; float data3 = 0.0; //长度单位换算 if (strcmp(op1, "in") == 0) i = 1; else if (strcmp(op1, "ft") == 0) i = 2; else if (strcmp(op1, "mm") == 0) i = 3; else if (strcmp(op1, "cm") == 0) i = 4; else if (strcmp(op1, "m") == 0) i = 5; else printf("* 请检查单位字母输入是否正确！\n"); switch(i) { case 1: //in if(strcmp(op2, "ft") == 0) data3 = data1/FT_TO_IN; else if(strcmp(op2, "mm") == 0) data3 = data1*(IN_TO_CM*10); else if(strcmp(op2, "cm") == 0) data3 = data1*IN_TO_CM; else if(strcmp(op2, "m") == 0) data3 = data1*(IN_TO_CM*0.01); else data3 = data1; break; case 2: //ft if(strcmp(op2, "ft") == 0) data3 = data1; else if(strcmp(op2, "mm") == 0) data3 = data1*(FT_TO_M*1000); else if(strcmp(op2, "cm") == 0) data3 = data1*(FT_TO_M*100); else if(strcmp(op2, "m") == 0) data3 = data1*FT_TO_M; else data3 = data1*FT_TO_IN; break; case 3: //mm if (strcmp(op2, "in") == 0) data3 = data1/IN_TO_CM*10; else if(strcmp(op2, "ft") == 0) data3 = data1/FT_TO_M*1000; else if(strcmp(op2, "mm") == 0) data3 = data1; else if(strcmp(op2, "cm") == 0) data3 = data1/10; else data3 = data1/1000; break; case 4: //cm if (strcmp(op2, "in") == 0) data3 = data1/IN_TO_CM; else if(strcmp(op2, "ft") == 0) data3 = data1/FT_TO_M *100; else if(strcmp(op2, "mm") == 0) data3 = data1*10; else if(strcmp(op2, "cm") == 0) data3 = data1; else data3 = data1/100; break; case 5: //m if (strcmp(op2, "in") == 0) data3 = data1/IN_TO_CM*100; else if(strcmp(op2, "ft") == 0) data3 = data1/FT_TO_M; else if(strcmp(op2, "mm") == 0) data3 = data1*1000; else if(strcmp(op2, "cm") == 0) data3 = data1*100; else data3 = data1; break; default: printf("* 无法换算，请重新输入！\n"); } printf("%.3f %s = %.3f %s\n",data1,op1,data3, op2); } // 质量单位换算 void WeightUnit(float data1, char op1[5], char op2[5]) { int i = 0; float data3 = 0.0; if (strcmp(op1, "lb") == 0) i = 1; else if (strcmp(op1, "oz") == 0) i = 2; else if (strcmp(op1, "g") == 0) i = 3; else if (strcmp(op1, "kg") == 0) i = 4; else if (strcmp(op1, "Jin") == 0) i = 5; else if (strcmp(op1, "ton") == 0) i = 6; else printf("* 请检查单位字母输入是否正确！\n"); switch(i) { case 1: //lb if(strcmp(op2, "oz") == 0) data3 = data1 * LB_TO_OZ; else if(strcmp(op2, "g") == 0) data3 = data1*LB_TO_G; else if(strcmp(op2, "kg") == 0) data3 = data1*LB_TO_G / 1000; else if(strcmp(op2, "Jin") == 0) data3 = data1*0.9071; else if(strcmp(op2, "ton") == 0) data3 = data1*LB_TO_G*1e-6; else data3 = data1; break; case 2: //oz if(strcmp(op2, "lb") == 0) data3 = data1 / LB_TO_OZ; else if(strcmp(op2, "g") == 0) data3 = data1 * OZ_TO_G; else if(strcmp(op2, "kg") == 0) data3 = data1*OZ_TO_G / 1e3; else if(strcmp(op2, "Jin") == 0) data3 = data1 * 0.056699; else if(strcmp(op2, "ton") == 0) data3 = data1*OZ_TO_G*1e-6; else data3 = data1; break; case 3://g if(strcmp(op2, "lb") == 0) data3 = data1/LB_TO_G; else if(strcmp(op2, "oz") == 0) data3 = data1 / OZ_TO_G; else if(strcmp(op2, "kg") == 0) data3 = data1/1000; else if(strcmp(op2, "Jin") == 0) data3 = data1 / 500; else if(strcmp(op2, "ton") == 0) data3 = data1*1e-6; else data3 = data1; break; case 4: //kg if(strcmp(op2, "lb") == 0) data3 = data1/LB_TO_G * 1000; else if(strcmp(op2, "oz") == 0) data3 = data1 / OZ_TO_G * 1000; else if(strcmp(op2, "g") == 0) data3 = data1*1000; else if(strcmp(op2, "Jin") == 0) data3 = data1 * 2; else if(strcmp(op2, "ton") == 0) data3 = data1*1e-3; else data3 = data1; break; case 5: //Jin if(strcmp(op2, "lb") == 0) data3 = data1 * 1.10231; else if(strcmp(op2, "oz") == 0) data3 = data1 * 17.63698; else if(strcmp(op2, "g") == 0) data3 = data1* 500; else if(strcmp(op2, "kg") == 0) data3 = data1 / 2; else if(strcmp(op2, "ton") == 0) data3 = data1*5*1e-4; else data3 = data1; break; case 6: //ton if(strcmp(op2, "lb") == 0) data3 = data1 * 2204.6226; else if(strcmp(op2, "oz") == 0) data3 = data1 * 35273.9619; else if(strcmp(op2, "g") == 0) data3 = data1 * 1e6; else if(strcmp(op2, "kg") == 0) data3 = data1 * 1e3; else if(strcmp(op2, "Jin") == 0) data3 = data1 * 2000; else data3 = data1; break; default: printf("* 无法换算，请重新输入！\n"); } printf("%.3f %s = %.3f %s\n",data1,op1,data3, op2); } // 面积单位换算 void AreaUnit(float data1, char op1[5], char op2[5]) { int i = 0; float data3 = 0.0; if (strcmp(op1, "hm2") == 0) i = 1; else if (strcmp(op1, "Mu") == 0) i = 2; else if (strcmp(op1, "m2") == 0) i = 3; else if (strcmp(op1, "ft2") == 0) i = 4; else printf("* 请检查单位字母输入是否正确！\n"); switch(i) { case 1: //hm2 if(strcmp(op2, "Mu") == 0) data3 = data1 * 15; else if(strcmp(op2, "m2") == 0) data3 = data1 * 10000; else if(strcmp(op2, "ft2") == 0) data3 = data1 * 107639.1042; else data3 = data1; break; case 2: //Mu if(strcmp(op2, "hm2") == 0) data3 = data1 / 15; else if(strcmp(op2, "m2") == 0) data3 = data1 / 15 * 10000; else if(strcmp(op2, "ft2") == 0) data3 = data1 * 7175.9403; else data3 = data1; break; case 3: //m2 if(strcmp(op2, "hm2") == 0) data3 = data1 / 1000; else if(strcmp(op2, "Mu") == 0) data3 = data1 * 0.0015 ; else if(strcmp(op2, "ft2") == 0) data3 = data1 * 10.76391; else data3 = data1; break; case 4: //ft2 if(strcmp(op2, "hm2") == 0) data3 = data1 * 9.2903e-6; else if(strcmp(op2, "Mu") == 0) data3 = data1 * 0.0001394; else if(strcmp(op2, "m2") == 0) data3 = data1 * 0.092903; else data3 = data1; break; default: printf("* 无法换算，请重新输入！\n"); } printf("%.3f %s = %.3f %s\n",data1,op1,data3, op2); } // 单位换算 void UnitConversion(float data1, char op1[5], char op2[5], int type) { if (type == 1) LengthUnit(data1, op1, op2); else if (type == 2) WeightUnit(data1, op1, op2); else AreaUnit(data1, op1, op2); } void main() { printf("********** 简易计算器 **********\n\n"); printf("注意：按ESC退出,按任意键继续！\n"); printf("单位用如下字母表示：\n"); printf("*********************************\n"); printf("* 长度单位换算\n* （英寸(in)、英尺(ft)、毫米(mm)、厘米(cm)、米(m)）；\n"); printf("* 质量单位换算\n* （磅(lb)、盎司(oz)、克(g)、千克(kg)、斤(Jin)、吨(ton)）；\n"); printf("* 面积单位换算\n* （公顷(hm2)、亩(Mu)、平方米(m2)、平方英尺(ft2)）；\n"); printf("*********************************\n"); float data1,data2; int a,type; char op,key = '\0'; char op1[5], op2[5]; printf("* 请选择操作：\n"); while((key = _getch()) != 0x1b) // 0x1b: ESC { printf("1.四则运算； 2.单位换算\n"); scanf_s("%d",&a); if(a == 1) { printf("* 请输入表达式（如：1+2）：\n"); scanf("%f%c%f",&data1,&op,&data2); FourArithmetic(data1, data2, op); // 四则运算 } else if(a == 2) { printf("* 请输入需要换算的单位（如：100m）:\n"); scanf("%f%s",&data1,&op1); printf("* 请输入换算后的单位（如：m）:\n"); scanf("%s",&op2); if (strcmp(op1, "ft") == 0 || strcmp(op1, "in") == 0 || strcmp(op1, "mm") == 0 \ || strcmp(op1, "cm") == 0|| strcmp(op1, "m") == 0) type = 1; else if (strcmp(op1, "lb") == 0 || strcmp(op1, "oz") == 0 || strcmp(op1, "g") == 0 \ || strcmp(op1, "kg") == 0 || strcmp(op1, "Jin") == 0 || strcmp(op1, "ton") == 0 ) type = 2; else if (strcmp(op1, "hm2") == 0 || strcmp(op1, "Mu") == 0 || strcmp(op1, "m2") == 0 \ || strcmp(op1, "ft2") == 0 ) type = 3; else printf("* 请检查单位字母输入是否正确！\n"); UnitConversion(data1, op1, op2, type); //单位换算 } else printf("* 暂不支持该选项，请重新选择！\n"); printf("\n******************************\n"); printf("* 请再次选择操作(ESC退出)：\n"); } system("pause"); }运行结果： 上述简易计算器比较简单，主要用了函数、while语句、if语句、switch语句、对输入字符串的判断等知识点，但是代码较多，或许有更简单的实现方式，笔者还在学习之中，不妥之处，请多指教。 |
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