20131005国庆作业5-5,5-6,5-7

5-5

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

    pyramid(5);

    return 0;
}
void pyramid(int n)
{
    int i,j;

    for(i=1;i<=n;i++){
        for(j=1;j<=n-1;j++)
            printf(" ");
        for(j=1;j<=i;j++)
            printf("%d",i);
        putchar('
');
    }
}

5-6

#include<stdio.h>
float result_real,result_imag;
int main(void)
{
    float imag1,imag2,real1,real2;
    void complex_prod(float real1,float imag1,float real2,float imag2);
    void complex_add(float real1,float imag1,float real2,float imag2);

    printf("Enter 1st complex number (real and imaginary):");
    scanf("%f%f",&real1,&imag1);
    printf("Enter 2nd complex number (real and imaginary):");
    scanf("%f%f",&real2,&imag2);
    complex_add(real1,imag1,real2,imag2);
    printf("addition of complex is%f+%fi
",result_real,result_imag);
    complex_prod(real1,imag1,real2,imag2);
    printf("product of complex is%f+%fi
",result_real,result_imag);

    return 0;
}

void complex_add(float real1,float imag1,float real2,float imag2)
{
    result_real=real1+real2;
    result_imag=imag1+imag2;
}
void complex_prod(float real1,float imag1,float real2,float imag2)
{
    result_real=real1*real2-imag1*imag2;
    result_imag=real1*imag2+real2*imag1;
}

 5-7

#include<stdio.h>
int x;
int f( );
int main(void)
{
    int a=1;
    x=a;
    a=f( );
    {
        int b=2;
        b=a+b;
        x=x+b;
    }
    printf("%d%d",a,x);

    return 0;
}
int f( )
{
    int x=4;

    return x;
}