Sum of series

code:
series: 1/1+1/2+1/3+….+1/N

#include<stdio.h>
int main()
{
    int N,i;
    float sum;
    printf("Enter N:");
    scanf("%d",&N);
    sum=0;
    i=1;
    do{
            sum=sum+1/(float)i;
            i++;
    }while(i<=N);
    printf("Sum of series: %f",sum);
    return 0;
}

series: 1/1-1/2+1/3-1/4+1/5….1/N
code:

#include<stdio.h>
int main()
{
    int i,N,sign;
    float sum;
    printf("Enter value of N:");
    scanf("%d",&N);
    sum=0;
    sign=1;
    do{
        sum=sum+(1.0/(float)i)*sign;
        i++;
        sign=sign*(-1);
    }while(i<=N);
    printf("Sum=%f",sum);

    return 0;
}

Series: 1^2/1!+2^2/2!+3^2/3!+4^2/4!+…..+N^2/N!

code:

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

int i, N, factorial;
float sum;
printf("Enter N:");
scanf("%d",&N);
for(sum=0,i=1,factorial=1;i<N;i++,factorial=factorial*i){
    sum=sum+(i*i)/(float)factorial;
}
printf("%f",sum);
return 0;
}

Series: 1^2/1!+3^2/2!+5^2/5!+….N^2/N!

code:

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

int i, N, x,factorial;
float sum;
printf("Enter number of terms N:");
scanf("%d",&N);

for(sum=0,i=1,factorial=1,x=1;i<=N;i++,factorial=factorial*(x-1)*x){
    sum=sum+(x*x)/(float)factorial;
    x=x+2;
}
printf("%f",sum);
return 0;
}

program to find summation of squares of all numbers  from 5 to 25
series: 25+36+49+…..+625=?

code:

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

int sum,i;
sum=0;
for(i=5;i<=25;i++)
{
    sum=sum+(i*i);
}
printf("%d",sum);

return 0;
}