第七章与心得

#include<stdio.h>
int main(void)

{
	int mynumber=38;
	int yournumber;

	printf("Input your number:");
	scanf("%d",&yournumber);
	if(yournumber==mynumber)
		printf("OK!you are right!
");
	else
		if(yournumber>mynumber)
			printf("Sorry!your number is bigger than my number!
");
		else
			printf("Sorry!your number is smaller than my number!
");

		return 0;

}

#include<stdio.h>
int main(void)
{
    int number;

    printf("Enter a number:");
    scanf("%d",&number);
    if(number%2==0){
        printf("The number is even.
");
    }
    else{
        printf("The number is odd.
");
    }

    return 0;

}

#include<stdio.h>
int main(void)
{
    int count,i,n;
    double grade,total;

    printf("Enter n:");
    scanf("%d",&n);
    total=0;
    count=0;
    for(i=1;i<=n;i++){
        printf("Enter grade #%d:",i);
        scanf("%if",&grade);
        total=total+grade;
        if(grade<60){
            count++;

        }

    }
    printf("Grade average=%.2f
",total/n);
    printf("Number of failures=%d
",count);
    return 0;

}

-

#include<stdio.h>
int main(void)
{
    double x,y;

    printf("Enter x:");
    scanf("%if",&x);
    if(x<0){
        y=0;

    }
    else if(x<=15){
            y=4*x/3;
    }
    else{
          y=2.5*x-10.5;
    }
    printf("f(%.2f)=%.2f
",x,y);

    return 0;
}

#include<stdio.h>
int main(void)
{
    double value1,value2;
    char op;
    printf("Type in an expression:");
    scanf("%if%c%if",&value1,&op,&value2);

    if(op=='+')
        printf("=%.2f
",value1+value2);
    else if(op=='-')
        printf("=%.2f
",value1-value2);
    else if(op=='*')
        printf("=%.2f
",value1*value2);
    else if(op'/')
        printf("=%.2f
",value1/value2);
    else
        printf("Unknown operator
");
    return 0;

}

          经过这几天的学习和打代码，我对C语言有了更深层的认识，也对着门课程和语言有了兴趣和好奇。

    一开始打得很慢，因为我以前对键盘不怎么熟悉，而且刚开始错误很多，虽然我很仔细的在打，还是会有错，但经过同学的帮助，我学会了怎样找错，以及怎样改正它们。

    就这样，看着我打出来的代码，我有一种莫名的喜悦，呵呵。

    问题：1.For语句和which语句的区别是什么；

         2.空格会影响结果吗；

         3.return 0是什么意思；