C107: Arrays

Array is used to store a list of data using a same name. data type can int, float, double, char. Array name is same as variable name, array size indicates how many data this array can store.

dataType arrayName[arraySize];

following example declares an array called num with size of the array is 5.

int num[5];

this means num can store up to 5 integer values. This statement only give name and allocates enough space for the array. It does not contain values. Array uses index to refer to particular elements in an array. Index 0 for the first element, 1 for second, and so on.

following line is to store a value as first element in num

num[0] = 2;

this statement will store 2 at index 0 of the num array. Let's assign value for every element in the array.

num[1] = 1;
num[2] = 4;
num[3] = 5;
num[4] = 3;

now all the space in the array contains a value. Take note that the index of last element in the array is (arraySize  - 1) because index start from 0.

now we can use the array value to do calculations

total  = num[2] + num[3];

this means total is 4 + 5, so the total value is 9.

we use for loop to find the sum of values stored in the array

int total = 0;
for(int i = 0; i < 5;i++){
  total = total + num[i];
}
prinf("Total num : %d\n", total);

the output is

Total num : 15

displaying all the element of num using for loop:

int total = 0;
for(int i = 0; i < 5;i++){
  int temp = i+1;
  printf("Element %d : %d\n",temp, num[i];
}

the output for the second example is

Element 1 : 2
Element 2 : 1
Element 3 : 4
Element 4 : 5
Element 5 : 3