第6讲【例4-21】输入一个数字（1～7），然后输出对应的代表星期几的英文单词。例4-22#include<stdio.h>main(){intscore;printf("Pleaseenterscore:");scanf("%d",&score);if(score<0||score>100)/*对输入数据的合法性进行检查*/printf("Inputerror!\n");elseif(score>=90)printf("%d--excellent\n",score);elseif(score>=80)printf("%d--good\n",score);elseif(score>=70)printf("%d—fitexactly\n",score);elseif(score>=60)printf("%d--pass\n",score);elseprintf("%d--fail\n",score);}方法二#include<stdio.h>voidmain(){intscore;printf("Pleaseenterscore:");scanf("%d",&score);if(score<0||score>100)printf(“Inputerror!\n”);else{switch(score/10){case10:case9:printf(“%d----excellent\n”,score);break;case8:printf(“%d----good\n”,score);break;case7:printf(“%d----fitexactly\n”,score);break;case6:printf(“%d----pass\n”,score);break;case5:case4:case3:case2:case1:case0:printf(“%d----fail\n”,score);break;}}}涉及到的语法知识-switch语句例4-24：计算器程序#include<stdio.h>intmain(){floatdata1,data2;/*定义两个操作符*/charop;/*定义运算符*/printf("Pleaseentertheexpression:");scanf("%f%c%f",&data1,&op,&data2);/*输入运算表达式*/switch(op){case'+':/*处理加法*/printf("%.2f+%.2f=%.2f\n",data1,data2,data1+data2);break;case'-':/*处理减法*/printf("%.2f-%.2f=%.2f\n",data1,data2,data1-data2);break;case'*':/*处理乘法*/printf("%.2f*%.2f=%.2f\n",data1,data2,data1*data2);break;case'/':/*处理除法*/if(0==data2)printf("Divisionbyzero!\n");elseprintf("%.2f/%.2f=%.2f\n",data1,data2,data1/data2);break;default:printf("Unknownoperator!\n");}}练习：程序输出结果是？问题常见语法错误-1常见语法错误-2小结作业